Charge sign solar modulation measured with the PAMELA experiment

The satellite-borne PAMELA experiment has been continuously collecting data since 15th June 2006, when it was launched from the Baikonur cosmodrome to detect the charged component of cosmic rays over a wide energy range and with an unprecedented statistics. The apparatus design is particularly suited for particle and antiparticle identification. Moreover, the PAMELA long flight duration allows to study the time variation of low energy (<30 GeV) cosmic rays, measuring the differential energy intensity of oppositely charged particles down to ˜70 MeV. We present preliminary results on the time-dependent electron, positron and proton fluxes measured at Earth between July 2006 and the end of 2014. This time period spans between the A<0 solar minimum of solar cycle 23 (2006-2009) till the middle of solar maximum of solar cycle 24. A direct comparison of electron, positron and proton spectra time variation and their differences allow a detailed study of charge-sign dependent solar modulation, both during solar minimum and at the polarity reversal of the heliospheric magnetic field.